1. General Description

2. Model Definition

• D634: Direct drive servo valve series

• 383: Medium‑high flow, high‑response configuration

• C: Revision C

3. Hydraulic Specifications

• Mounting: ISO 4401 Size 05 (NG10)

• Max working pressure (P, A, B): 350 barMoog Inc.

• Max T‑port pressure (without Y): 50 barMoog Inc.

• Rated flow (Δp = 35 bar): 100 L/min

• Max flow: approx 150 L/min

• Internal leakage: ≤2.3 L/min

• Fluid: ISO 11158 mineral oil

• Fluid temperature: −20 °C to +80 °C

• Fluid cleanliness: ISO 4406 17/14/11

• Weight: approx 7.0 kg

4. Dynamic Performance

• Full‑stroke step response: ≤18 ms

• −3 dB bandwidth: 58–68 Hz

• Hysteresis: <0.22% of full scale

• Position resolution: <0.11% of full scale

• Null drift (ΔT = 55 K): <1.3% of full scale

5. Electrical Specifications

• Supply voltage: 24 VDC (18–32 VDC)Moog Inc.

• Max operating current: 2.7 A

• Standard control signal: ±10 VMoog Inc.

• Optional signals: ±10 mA, 4–20 mAMoog Inc.

• Spool position feedback: 0–10 VDC

• Connector: M18, 6‑pin + PE, IP65Moog Inc.

• Ambient temperature: −20 °C to +60 °C

• EMC: CE compliant

6. Key Features

• Pilotless direct drive: simpler installation, lower maintenance

• High dynamic response: fast settling for high‑speed closed loops

• Pressure‑independent dynamics: stable performance under varying loads

• Closed‑loop position control: excellent linearity and repeatability

• Spring‑centered fail‑safe: safe shutdown on power loss

• Integrated electronics: compact, rugged, EMI‑hardened

7. Applications

• High‑speed hydraulic presses

• Automotive & aerospace fatigue test rigs

• Medium‑frequency vibration simulation tables

• Precision position, velocity, and pressure control systems

8. Pin Assignment

1. +24 VDC power

2. Power ground

3. Command +

4. Command −

5. Position feedback output

6. Feedback ground

   PE: Protective earth

   Use shielded twisted pair for signal wiring.